Herbicidal compounds having the structural formula ##STR2## wherein R through R.sup.9 are as defined below and R.sup.10 is (a) hydrogen, (b) C.sub.1 -C.sub.6 alkyl, (c) C.sub.4 -C.sub.6 cycloalkyl, (d) substituted C.sub.1 -C.sub.6 alkyl, (e) phenyl, (f) substituted phenyl, (g) C.sub.1 -C.sub.6 alkoxy, (h) benzyl, (i) phenethyl, (j) C.sub.1 -C.sub.4 alkyl--C(O)--, (k) C.sub.1 -C.sub.4 alkyoxy--C(O)--, (l) C.sub.2 -C.sub.6 alkenyl, or (m) C.sub.2 -C.sub.6 alkynyl; are described in U.S. Pat. No. 4,775,411 which is incorporated herein by reference.